The Morphology/Immunology/Biochemistry Section of Core C will provide the various projects in the program with necessary expertise, facilities and support to perform routine light microscopy, immunofluorescent microscopy and any other specialized morphological, pathological and immunohistochemical support required. In addition, the core will provide the wherewithal to produce and test highly specific antibodies against gap junction and minK proteins and synthetic peptides for use in the various projects. Finally, the core will provide routine biochemical studies of coronary sinus effluent in Langendorff-perfused rabbit hearts. The Molecular Biology Section of Core C will supply the program with the capabilities to prepare and test the ole of specific domains of the connexin molecule in gap junction and human minK structure and function studies. By the services provided by Core C of specific molecular domains in connexin's and minK synthesis, insertion into the plasma membrane, possible oligomerization into a multimeric structure and formation of competent gap junctions will be able to be explored. Specifically the responsibilities of the Molecular Biology Section of Core C will include the growth and purification of DNA; site-specific mutagenesis of the connexin and minK cDNA's; production of cRNA and checking of the cRNA in in vitro translation assays; DNA sequencing of mutagenized connexin and minK cDNA's; preparation and microinjection of frog oocytes; and development of the techniques necessary in the preparation of myocardial mRNA and its expression and recording of ion channel activity in oocytes microinjected with myocardial mRNA.